Avalanche Forecast

Issued: Dec 27th, 2013 7:23AM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is moderate. Known problems include Storm Slabs and Persistent Slabs.

Avalanche Canada Peter, Avalanche Canada

Summary

Confidence

Poor - Due to the number of field observations

Weather Forecast

Saturday: Cloudy with flurries or periods of snow developing later in the day – 5-10 cm. The freezing level is at valley bottom and winds are light to moderate from the west-southwest. Sunday: Mainly cloudy with a chance of flurries. The freezing level is near valley bottom but there is a chance of an above freezing layer near 1500 m. Winds are light from the W-SW. Monday: Periods of snow. The freezing level is near valley bottom and winds are light to moderate from the SW.

Avalanche Summary

No new avalanches have been reported, but observations are very limited. Areas with heavier recent snowfall likely experienced a natural avalanche cycle on Thursday. Rider triggering remains a concern in steeper terrain and wind loaded features, primarily at and above treeline.

Snowpack Summary

Storm snow totals in the region are around 40-50 cm, with moist or wet snow below treeline. Periods of moderate to strong W-SW winds were likely over the past couple days. Expect dense wind slabs in exposed lee terrain and cross-loaded features. Between 40 and 80 cm of snow sits on a crust that extends up to treeline and possibly beyond. This interface was "popping" under easy loads in snowpack tests a few days ago. A new surface rain crust will probably form at lower elevations as temperatures cool tonight. Deeper in the snow pack a layer of facets/surface hoar formed in early December can be found in the top 100cm in the Ashman. The mid and lower snowpack is still structurally weak and faceted. Depth hoar and an early season crust exist near the ground.

Problems

Storm Slabs

An icon showing Storm Slabs
It may be possible to trigger fresh storm and wind slabs, particularly in steep exposed N-E facing terrain, where wind loading has occurred, and at high elevations, where a surface rain crust is absent.
Choose conservative lines and watch for clues of instability.>The new snow will require several days to settle and stabilize.>Be cautious as you transition into wind affected terrain.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 4

Persistent Slabs

An icon showing Persistent Slabs
There is not much news on the buried mid-December rain crust. Watch for clues of instability and be prepared to dig and investigate if you plan on venturing into more committing terrain.
Whumpfing, shooting cracks and recent avalanches are all strong inicators of unstable snowpack.>Avoid convexities or areas with a thin or variable snowpack.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 5

Valid until: Dec 28th, 2013 2:00PM